PROJECTION ZOOM LENS AND PROJECTION TYPE DISPLAY DEVICE

摘要

A projection zoom lens is essentially constituted by, in order from the magnification side: a negative first lens group; a positive second lens group; a third lens group; a positive fourth lens group; a fifth lens group; and a positive sixth lens group. The distance between the first and second lens groups is shorter, the distance between the second and third lens groups is longer, the distance between the third and fourth lens groups is shorter, the distance between the fourth and the fifth lens groups is longer, and the distance between the fifth and sixth lens groups is longer at the telephoto end than at the wide angle end. A lens having a negative refractive power in the paraxial region is provided most toward the magnification side in the first lens group. The fifth lens group has a negative lens.

主权项

1. A projection zoom lens consisting of, in order from the magnification side to the reduction side:
a first lens group having a negative refractive power; a second lens group having a positive refractive power; a third lens group; a fourth lens group having a positive refractive power; a fifth lens group; and a sixth lens group having a positive refractive power; the distances among all adjacent lens groups changing when changing magnification; the distance between the first lens group and the second lens group being shorter at the telephoto end than at the wide angle end; the distance between the second lens group and the third lens group being longer at the telephoto end than at the wide angle end; the distance between the third lens group and the fourth lens group being shorter at the telephoto end than at the wide angle end; the distance between the fourth lens group and the fifth lens group being longer at the telephoto end than at the wide angle end; the distance between the fifth lens group and the sixth lens group being longer at the telephoto end than at the wide angle end; a lens having a concave surface toward the magnification side in the paraxial region and a negative refractive power in the paraxial region being provided most toward the magnification side in the first lens group; and the fifth lens group having at least one negative lens.